<template>
    <div>
        <router-link tag="div"
            to="/"
            class="header-abs"
            v-show="showAbs">
            <span class="iconfont header-abs-back">&#xe624;</span>
        </router-link>
        <div class="header-fixed"
            v-show="!showAbs"
            :style="opacityStyle">
            景点详情
            <router-link to="/">
                <div class="header-back">
                    <span class="iconfont header-fixed-back">&#xe624;</span>
                </div>
            </router-link>
        </div>

    </div>
</template>

<script>
     export default {
        name: "DetailHeader",
        data(){
            return{
                showAbs:true,
                opacityStyle:{
                    opacity: 0
                }
            }
        },
        activated(){
             window.addEventListener('scroll',this.handleScroll)
        },
        deactivated(){
            //离开页面时移除事件
            window.removeEventListener('scroll',this.handleScroll)
        },
        methods:{
            handleScroll(){
                const top = document.documentElement.scrollTop
                if(top > 60 ){
                    let opacity = top/140
                    opacity = opacity > 1 ? 1:opacity
                    // this.opacityStyle ={
                    //     opacity:opacity
                    // }
                    this.opacityStyle={opacity}
                    this.showAbs = false
                }else {
                    this.showAbs= true
                }
            }
        }
    }
</script>

<style lang="stylus" scoped>
    @import '../../assets/style/varibles.styl'
    .header-abs
        position: absolute
        left:.2rem
        top:.2rem
        width:.8rem
        height:.8rem
        line-height .8rem
        text-align center
        border-radius .4rem
        background:rgb(0,0,0,.8)
        .header-abs-back
            color: #ccc
            font-size .4rem
    .header-fixed
        z-index 2
        top 0
        left 0
        right 0
        position fixed
        height: $headerHeight
        line-height $headerHeight
        text-align: center
        color: #fff
        background $bgColor
        font-size .32rem
        .header-fixed-back
            position absolute
            top:0
            left:0
            text-align center
            width:.64rem
            font-size .4rem
            color: #fff
</style>